Coffee makers pass water through ground coffee beans to produce brewed coffee. Similarly, water can be passed through tea leaves, or similar, to produce brewed tea. Since the processes are similar, for the sake of brevity, processes by which brewed coffee is made will be described with more particularity. Usually, water is deposited on top of dried ground coffee beans residing in a filter, which is supported by a filter basket. The flavor and color that is extracted from the ground coffee is a function of the intermixing of the hot water with the ground coffee during the time the hot water is traveling through the ground coffee and the filter en route to a carafe that collects the brewed beverage.
Attempts have been made to increase the intermixing of the hot water with the ground coffee during the time when the hot water is traveling through the ground coffee. Such attempts include the following: stirring the coffee grounds and water mixture with a blade that is suspended in the filter basket, agitating the entire filter basket using an ultrasonic vibrating device, rotating the filter basket about a vertical axis, and introducing water at a high velocity, as compared to the velocity at which the water is introduced in a conventional drip coffee maker, into the filter basket.
Stirring the ground coffee and hot water mixture has been found to be adequate to extract more flavor from the same amount of dried coffee as compared to simply passing water through the ground coffee. The blade used in the mixing process, however, should be cleaned after each brewing process, which requires the person making the coffee to clean an extra component of the coffee maker. Additionally, it can be difficult to fit the blade into the filter basket when a large amount of dried ground coffee has been placed in the filter basket. Moreover, removal of the filter basket from a conventional drip coffee maker that uses a basket filter can require a complex mechanism to retract the blade.
Agitating the entire filter basket by the ultrasonic vibrating device produces localized eddies that do not result in adequate mixing of the ground coffee in the hot water. Additionally, the ultrasonic vibrator can be loud and also result in the vibration of other components of the coffee maker, especially those that are in proximity to or in direct contact with the filter basket.
Rotating the entire filter basket about a vertical axis does not result in adequate mixing of the contents in the filter basket until the inertial forces of the water and coffee grounds mixture are overcome. Overcoming the initial inertial forces may take more time than the amount of time required for water to pass through the coffee grounds en route to the brewed coffee reservoir. Also, a vortex can form which can result in water flowing over the side of the filter basket.
Introducing hot water at a high velocity can be messy if the contents of the filter basket are not well confined and/or sealed. Additionally, an expensive pump may be required to deliver the water at the high velocity.